I made my first visit to Kew Gardens in London in the early 1980s. It is a beautiful and highly scientific place and in May this year, it produced an extraordinarily important report on The State of the World’s Plants.

The good news is that the staff now believe that there are 390,000 species of plants on earth. The director of science at Kew Gardens, Kathy Willis, spoke to Damian Carrington of The Guardian about the importance of plants for humans.

Willis said, “Plants are absolutely fundamental to humankind. Plants provide us with everything—food, fuel, medicine, timber and are incredibly important for our climate regulation. Without plants we would not be here.”

Willis is encouraged by the fact that scientists are still discovering new species of trees and plants each year. In 2015, over 2,000 new species of plants were isolated, including five different species of onion.

Willis believes, “There are huge areas of the world where we don’t just know what is going on. They may hold the future of food, because the genetic basis of our food is becoming poorer and poorer.”

She added that the reason for this is simple, as for hundreds of years humans have bred crops to produce greater yields, to such an extent that the genes that protected the plant from pests and disease have been bred out of them.

She explained that there are quite a number of important plants which are used across the globe which have little genetic diversity. Included on the list are bananas, sorghum and aubergines.

If these plants are to continue to be part of our diet, we will need to furnish them with valuable traits from wild varieties to make them more resilient in the face of pests, disease and the uncertainty which climate change will bring to our weather in the future.

But plants provide us with more than food. More than 17,000 plants are used in human medicine. It is estimated that more than 50 per cent of 150 prescribed drugs, with an economic value of more than US$80 billion ($620 billion) are derived from discoveries in the wild.

Edward O. Wilson, a professor emeritus of biology at Harvard University, is convinced that “it is no exaggeration to say that the search for natural medicine is a race between science and extinction, and will become critical, as more forests fall and coral reefs bleach and disintegrate.”

The bad news from the Kew Gardens’ The State of the World’s Plants report is that we are losing so many plants through extinction. These experts believe that the figure could be as high as 20 per cent of all plants.

In Praise Be: On care for our common home (Laudato Si’), Pope Francis bemoans the fact that “the Earth’s resources are being plundered because of short-sighted approaches to the economy, commerce and production” (No.34).

The main culprits, according to the The State of the World’s Plants, are the destruction of tropical rainforests in order to grow palm oil and produce beef, followed by timber production and the construction of buildings and infrastructure.

At the moment, climate change is not one of the principle causes of extinction, but that might change as temperatures rises. Willis is worried about the future of coffee, because rising temperatures make the beans impossible to grow and lead to an increase in disease, as is now evident in Ethiopia.

Willis is convinced that humans “are facing some devastating realities if we do not take stock and re-examine our priorities and efforts.”

The report is the first of what will be an annual benchmark analysis to set out what is known—and not known—about plants and will highlight critical issues, as well as address how they can be tackled.

“I am reasonably optimistic,” Willis said. “Once you know, you can do something about it. The biggest problem is not knowing.”

The call to protect biodiversity is at the heart of Pope Francis’ encyclical. In the past we often believed that all creation was there primarily to meet human needs. But that is not so according to Pope Francis.

“The creatures of the earth were not created in the first instance for us to dispose of as we will, regardless of their place in God’s plan. They are primarily for ‘the fulfillment of God’s own unfolding plan for Creation’” (No.53).

In the next paragraph he tells us that “everything is, as it were, a caress of God” (No.84).